Automatic electrically operated water heater



Jan. 29, 1957 B. F. SAWYER 2,779,855

AUTOMATIC ELECTRICALLY OPERATED WATER HEATER Filed June 14. 1955 1nVGHTOf Bel d F. Sawyer I United States Patent 9 AUTOMATIC ELECTRICALLYOPERATED WATER HEATER Boyd F. Sawyer, Bucyrus, Ohio Application June 14,1955, Serial No. 515,415

2 Claims. (Cl. 219-39) This invention relates to new and usefulimprovements and structural refinements in electric water heatingsystems, particularly of the type used for commercial or residentialspace heating purposes, and the principal obiect of the invention is toprovide a compact heating unit which is extremely simple inconstruction, highly economical in operation, and adaptable toexpeditions and simple installation, maintainance and repair.

An important feature of the invention resides in the provision ofelectric means for automatically controlling the operation of theheating unit, whereby to assure even, dependable heating at all times.

Another important feature of the invention involves the use of heatingelements and controls of a standard variety, such as are readilyavailable on the market and may be readily procured for installation andreplacement purposes without undue expense and loss of time.

A further important feature of the invention resides in the constructionof the boiler itself, the same being adapted to retard the flow of watertherethrough and thus assure rapid and efficient heating.

With the foregoing more important objects and features in view and suchother objects and features as may be come apparent as this specificationproceeds, the invention resides in the details of construction andarrangeent of parts substantially as shown in the accompanying drawing,wherein like characters of reference are used to designate like partsand wherein:

Figure 1 is a vertical sectional view of the heating unit, alsoillustrating diagrammatically the associated controls;

Figure 2 is a cross-sectional detail, on an enlarged scale, takensubstantially in the plane of the line 22 in Figure 1; and

Figure 3 is a plan view of the baffle plate used in the boiler.

Referring now to the accompanying drawing in detail, the heating unit isdesignated generally by the reference numeral comprises a verticallyelongated boiler disposed in a suitable casing 12 having insulatingmaterial 13 therein as shown, the casing being supported by a pluralityof legs 14.

A hot Water outlet pipe 15 extends from the upper end portion of theboiler 11 for connection to radiators, or the like (not shown). Atubular, horizontally disposed duct 15 extends laterally into the lowerend portion of the boiler 11 and is open at its inner end so as tocommunicate with the interior of the boiler. The outer end portion ofthe duct 16 is accommodated in a lateral dome or extension 17 providedat one side of the casing 12.

A cold water inlet pipe 18, carrying the return from the aforementionedradiators, or the like, is connected to the outer end portion of theduct 16, so as to complete the water circuit through the system. Asuitable electric pump 19 is provided on the inlet pipe 18 to effectwater circulation.

A pair of primary electric heating elements 20, 21 are ice provided inthe boiler 11, the former being disposed longitudinally in the duct 16while the latter is disposed vertically in the upper end portion of theboiler adjacent the outlet pipe 15. In addition, a secondary electricheating element 22 is disposed horizontally in the intermediate portionof the boiler, as shown.

In order to facilitate rapid and etficient heating of water in theboiler, a transverse bathe plate 23 is provided between the duct 16 andthe heating element 22, the plate 23 having a restricted water passage24 therein, whereby to materially retard the flow of water through theboiler, that is, from the inlet pipe 18 to the outlet pipe 15.

The operation of the heating elements 20, 21, 22 as well as of the pump19 is electrically automatically controlled, such control meanscomprising a room temperature responsive thermostat 25 in circuit with arelay 26 which, in turn, is in circuit with the primary heating elements20, 21 as shown at 27, 28, respectively. The thermostat 25 is alsoconnected to a second relay 29 which is in circuit with the pump 19 asindicated at 30. A water temperature responsive cut-out 31 is providedon the hot water outlet pipe 15 in circuit with the relay 26 as shown at32, and the pipe 15 also carries a suitable water pressure gauge 33. Therelays 26, 29 are connected to a transformer 34 having a connection 35to a source of electric power, while the secondary heating element 22 isconnected to this transformer, as indicated at 36. The element 22 iscontrolled by a boiler temperature responsive thermostat 37 mounteddirectly on the wall of the boiler, the connection of the element 22 andthe thermostat 37 being illustrated at 38.

When the apparatus is placed in use, the automatic controls afford acontinuous circulation of water through the system with the watertemperature so regulated that the temperature at the outlet 15 somewhatmore than equalises the heat loss in the space being heated. Thus, aconstant room or space temperature is maintained and intermittentover-heating or under-heating is eliminated.

The primary heating elements 21), 21 are energized through the relay 26when additional heat is called for by the thermostat 25 and aresimilarly de-energized when a predetermined temperature in the room isreached. On the other hand, the element 22, acting in response to theboiler thermostat 37, operates independently of the elements 20, 21 and,in moderate weather, is sufficient to maintain the water temperature byitself at the desired degree. The pump 19, controlled through the relay29 by the thermostat 25, operates simultaneously with the primaryelements 20, 21 and when these elements and the pump are not inoperation, the heating eifect of the element 22 will produce aconvection current for circulating water within the system without theuse of the pump.

In the event that the thermostat 25 should become defective and fail tode-energize the elements 20, 21 upon reaching of a predetermined degreeof temperature, the cut-out 31 on the outlet pipe 15 will automaticallydeenergize the elements 29, 21 while permitting operation of the pump 19through the relay 29 of circulate the water through the system. Asalready noted, the cut-out 31 acts through the relay 26 to control theelements 20, 21, independently of the relay 29 controlling the pump 19.

As will be observed, the relays 26, 29 and the transformer 34 may bemounted in a suitable box or panel 39, already wired, so that the entiresystem may be readily installed by simply connecting the same to asource of electric power and completing the connections of the pipes 15,18 to radiators, or the like.

While in the foregoing there has been described and shown the preferredembodiment of the invention, various modifications may become apparentto those skilled in the art to which the invention relates. Accordingly,it not desired to limit the invention to this disclosure and variousmodifications may be'resorted to, such as may be lie Within the spiritand scope of the appended claims.

What is claimed as new is:

1; In an electric water heating system, the combination of a verticallyelongated boiler, a hot water outlet pipe extending from the upperportion of said boiler, a tubular duct extending laterally into thelower end portion of the boiler and open at its inner end, a cold waterinlet pipe connected to the outer end of said duct, an electric heatingelement provided in said duct and connected to a source of electricpower, a transverse baifie plate provided in the boiler above said duct,said bafile plate having a restricted water passage therein, whereby toretard the flow of water from said duct to said outlet, an additionalelectric heating element provided said boiler above said bafile plate.

2. In an electric water heating system, the combination of a verticallyelongated boiler, a hot water outlet pipe extending from the upperportion of said boiler, a tubular duct extending laterally into thelower portion of the boiler and open at its inner end, a cold waterinlet pipe connected to the outer end of said duct, an electric heatingelement provided in said duct and connected to a source of electricpower, a transverse baffle plate provided in the boiler above said ductand having a restricted water passage therein whereby to retard the flowof water from the duct to said outlet, an additional electric heatingelement provided in the boiler above said bafile plate and connected toa source of electric power, a room temperature responsive thermostat incircuit with the first metnioned element, a boiler temperatureresponsive thermostat in circuit with the second mentioned elementwhereby the second mentioned element may operate selectively inexclusion of and together with the first mentioned element, an electriccirculating pump provided on said cold water inlet pipe, said pump beingin circuit with said room temperature responsive thermostat foroperation together with the first mentioned element, and temperatureresponsive rneans provided on said hot water outlet pipe fordisconnecting the first mentioned element from the power sourceindependently of said pump.

References Cited in the file of this patent UNITED STATES PATENTS1,692,646 Gannon et al Nov, 20, 1928 2,151,854 Knapp Mar. 28, 19392,375,871 Reifenberg May 15, 1945 2,511,635 Holmes June 13, 1950

